Machine for wrapping plastic materials



3 hreets-Sheet 1`- July 3 1945- A. RUSSELL rs1-Al.

MACHINE FOR WRAPPING PLASTIC MATERIALS Filed March 9. l194.l

July 3,1945. A. RUSSEL; m; 2,379,655

MACHINE FOR,WRAPPING PLASTlC MATERIALS 5| ,l I 30 i I g V I inv 2 I:

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July 3, 1945. ARUSSELL m. f 2,379,655 l A MACHINE FOR WRAPPING PLASTICMATERIALS Filed Mal-5&9, 19:14 s sheets-sheet s ping wheel.

Fatented diy 3, i945' MACHNE FR WRAPPING PLASTIC MATER/limbs AlexanderRussell, Matthew Parker, and Richard Anson Harris, Leeds, England,assgnors to The Fergrove Machinery Company Limited, Leeds, England, acompany of Great Britain application Maren 9, 1944, seriai No.' 525.685

lin Great Britain May 5, 1943 (ci. sis-2) 6 -Cllaimsz In the wrapping bymechanical means of plastic materials, such for example as margarine,butter or the like, difficulty is often encountered in transferring thematerial from one to another of the various members of the machineduring the process of wrapping, because of the adhesion .,-of theplastic material to the members. To overf come this trouble a liquid,such as water, is some- Hitherto it has been common practice in thistype of machine to extrude plastic material from a feed hopper by meansof rotating worms into a die chamber having a horizontally slidable topcover, and a bottom formed by a vertically slidable die plunger. The dieplunger lifts the extruded block or print into one of several sets ofgripper jaws carried on a wrapping wheel, the block being arranged tocontact and carry with it a wrapper suitably interposed in its pathbetween the die chamber and the gripper jaws. To slide the block fromthe die plunger, the gripper jaws are moved horizontally, whilst the dieplunger dwells in its top position.

Usually there are four sets `of gripper jaws on the wrapping wheel, andeach set requires mechanism for its movement, thus adding considerableweight to the wrapping wheel. Alsothe space required for the gripper jawmechanism and movement sets a limit to the minimum size of the Wrappingwheel, so that the eiect ofthe weight cannot be offset by reducing thesize of the wrap- Furthermore, the time required for the long dieplunger stroke demanded byv this scheme reduces the amount of timeavailable for extruding the material into the die chamber. There appearsalso to be some risk of damage to the moving jaw type of machine, owingto the possible breakage of certain springs. These springs retain themoving jaws against stops on the wrapping Wheel, except when the jawsare pulled over the plunger position to receive a block, and they haveto' be strong enough to ensure without fail that the blocks are slid oithe plunger when the jaws are permitted to return to their stops. i

To minimize this risk of damage, the springs are often duplicated, butas each one must be capable of carrying on if the-other one breaks, thisremedy entails doubling the weight of the springs (which isconsiderable) and doubling the load on the gripper jaw movement. l

The object of the present invention is Ato pro- Vide an alternativemechanism for transferring to the wrapping wheel the wrappers and printsof plastic material delivered from the die chamber, which will vpermitof the use of a simpler and lighter wrapping wheel, and of av shorterdie plunger stroke, thus enabling a larger share of the available timeto be devoted to the extrusion of the plastic material into'the diechamber and theA risk of breakage of parts associated with the.

wrapping wheel to be eliminated.

The invention provides a machine for wrapping plastic materials, suchfor example as butter, margarine or the like, which includes anextrusion device for forming the plastic material into shaped blocks, alifting plunger for receiving the blocks from the extrusion device andoperative at each machine cycle to deliver into the jaws of a wrappingwheel one of said blocks and a'wrapper, said lifting plunger beingarranged to move in a triangular path, viz. first upwardly to feed theblock into the jaws, then horizontally or almost so to a position inwhich it is 'clear of the block held in the jaws, and finally diagonallydownwards to its starting position.

They invention thus permits of the use of a wrapping wheel furnishedwith pairs of stationary jaws. By the expression stationary, we meanthat the jaws do not execute any horizontal movement for the purpose ofsliding the print oil .the lifting plunger, this horizontal movementbeing executed by the lifting plunger, as stated. We do not, however,exclude the provision of the usual opening and closing movement requiredto enable the jawsfto receive and embrace the print.'

l Owing to the elimination of horizontal movement ofthe jaws, theconstruction of the wrapping wheel is much simplied and the wheel can bemade smaller and lighter and the risk of breakage of springsfor'controlling the horizontal movement of the'jaws is removed. "Also,since the die plunger no longer has to operate also as a liftingplunger, its stroke is shortened and more time is available for feedingthe plastic material into the die ,chambery `The machine speed cantherefore be increased as the result of the more i favourable timedistribution `and the simplification of thewrapping wheel.

. One specic 'form of wrapping machine' according to the invention willnow be described in further detail; by way of example, with reference tothe accompanying drawings, in which A Fig. 1 isi a side elevation,partly in section,

showing the die chamber, lifting plunger, operating gear therefore, andpartei the wrapping wheel, the lifting plunger being shown ln its downposition and about to commence its upstroke,

Fig. 2 is a corresponding plan view, and

Figs.'3, 4 and 5 are views similar to Fig. 1 showing respectively thepositions occupied by the parts at the conclusion of the upstroke of thelifting plunger, at the end of its horizontal sliding movement, andafter its return to the down position. i

Like reference numerals indicate like parts throughout the figures.

The plastic material is fed from a hopper by intermittently rotatingfeed worms, one of which is shown at I in Fig. 1, to an extrusion box Hlocated to one side of a die chamber l2. In the die chamber is disposeda reciprocating die plunger I3 which constitutes the bottom of the diechamber. This serves to lift out of the die chamber a succession ofprints I4 of the extruded plastic material, which are slid off the topof the die plunger by a sliding plate I5 constituting a'top cover forthe die chamber.

The operation of the die chamber and associated parts is fully describedin our copending United States application Serial No. 525,684 and itwill be sufficient to state here that the plastic material is extrudedinto the die chamber when the die plunger I3 is in its down position asindicated in Fig. 3, the top cover I5 then closing the top of the diechamber. A knife I6 then moves up to close the extrusion orifice betweenthe die chamber I2 and the extrusion box I I (see Fig. 4), the top coverI5 moves to the right to open the top of the die chamber, and the die gplunger I3 moves up to lift the shaped block or print I4 of plasticmaterial out of the die chamber asshown in Fig. 5. In this position theupper surface of the die plunger I3 is level with the undersurface ofthe top cover I5.

The top cover I5 then moves to the left, and an upstanding flange llthereon pushes the print off the die plunger i3, which remains dwellingin its up position, on to a reciprocating lifting plunger d8 (see Fig.1), the knife I6 meanwhile returning to the down position. The dieplunger,

then return to its down position (Fig. 3) and a fresh extrusionoperation commences (see Fig. 3).

The sliding top cover I5 ythus transfers the prints in succession to thelifting plunger` I8, which receives them when in its down position. Aswill be clear from Fig. 1, the upper surface of the lifting plunger I8,when in its down position, is level with the position occupied by theupper surface of the die plunger I3 when in its top position. Thelifting plunger is operated bythe which is so designed that, startingfrom the down position of the lifting plunger, the latter is rst wheel20 having four pairs of jaws, the print carrying with it a wrapper 2Iwhich has meanwhile been fed along guides 22 Ainto the path of theliftingv plunger by the mechanism described in our copending UnitedStates application Serial No. 511,670. The wrapper is thus folded ininverted U formation about the print.

The gripping jaws I9 are hinged at 53 and connected by meshing quadrantsso as to open and close together. They are spring urged towards thevclosed position. These details are not i gages a roller practice inwrapping wheels for wrapping toffee and other non-plastic materials. Thejaws are opened, by cam action, prior to entry of the print and arethereafter permitted to close against the sides of the print. This iseffected by a cam 54, which is periodically rocked to and fro and enthejaws.

The' lifting plunger dwells in the up position,r

and after the jaws have closed on the print, the plunger is movedsideways horizontally (or nearly so), sufiiciently to slide it clear ofthe undersurface of the print (see Fig. 4). Thereafter the plunger isreturned diagonally into its down position. Its upper surface thereforemoves in a triangular path, shown in chain dotted lines in Fig;` 1, i.e. first of all vertically up, then horizontally and finally in astraight inclined path back to the down position.

During or immediately after the horizontal sliding movement of thelifting plunger, a folder (not shown) moves in, in known manner, to foldagainst the bottom of the print the depending' end of the wrapper at theside remote from the h plunger (see Fig. 4). The wrapping wheel thenmoves, see Fig. 5, through 90 to transfer the print to the `nextwrapping station. On its way, the other depending end of the wrapper isfolded against ,the undersurface of the print by a stationary folder 23.This folder is stationary in the sense that it occupies a fixed positionduring movement of.- the wrapping wheel. It is, however, lifted by a camand link mechanism, as

later described, out of the way of the lifting plunger during thehorizontal movement thereof, and is returned to its operative positionafter the plunger has passed and before the wrapping wheel begins torotate. 1 The cam and linkage mechanism for actuating the liftingplunger I8 operates as follows:

To a fixed member 24 of the machine framework (Fig. 2) is attachedavbracket 25 carryingf a xed guide 26 on which is slidably mounted acarriage 21. To the carriage are pivoted parallel links 30, 3Isupporting the lifting plunger I8 plunger I8 by a lever 32 pivoted on ashaft 33 and carrying a roller 34 engaging a track in a cam 35 on thecam shaft 36, the lever being connectedto the upper link 3|) of theparallel linkage by a lifting link 31. A spring 38, attached at itsupper end-to the bracket 25, supports the Weight of the parallel linkageand lifting gear.

l55 cam and linkage mechanism described below,k

illustrated because the construction is common'flti Thehorizontalmovement is imparted to the' lifting plunger by a link 29pivoted at one end by a pin 28 to the carriage 2'I and at the other endto a triangular lever 39 pivoted to the shaft 33 and carrying a roller40 engaging a track in ,l

a cam 4I on the cam shaft 35. 'Ihe cams '35, 4I are so shaped that,after the plunger I8 has executed a substantially vertical upwardmovement under the action of the cam 35, it dwells in the up positionwhile the cam 4I imparts to it a substantially horizontal, movementtowards the left, so moving it from the position shown in Fig. 3 to thatin Fig. Il. Thereafter both cams operate simultaneously on the plungerto return it diagonally` downwards to its down position (Fig. 5) 'I'helinks 30, V3I of the parallel linkage are guided in their movementsby'the forked upper end'of a guide bracket 42 fixed to the machineframework.

The'stationary fumer 234s uned 'from its oper-5 ative position to theposition shown vin Fig. 4 to on an extension 56 of one of' The liftingmovement is communicated to'thegeraete permit of the horizontal sidewaysmovement of the lifting plunger, by means of a cam 43 on a shaft 44. Atrack in the cam engages a roller 45 on a lever 46 fixed to a shaft 41.Also fast on the shaft 4l is a lever 48 connected by a link 49 to acrank 50 on a shaft 5I supporting the folder 23. The cam 43 thus rocksthe shaft 5l sufciently to lift the right hand end of the folder 23 outof the path of the lifting plunger i8. The lever 46 also operates thetop presser plate mentioned above through the agency of a link 52.

What we claim as our invention and desireto secure by Letters Patent is:

vl. In a machine for shaping and wrapping plastic materials, having anextrusion'device for forming the plastic material into shaped blocks anda wrapping wheel for wrapping the blocks so formed, the combination withthe wrapping wheel pf a lifting plunger for receiving said blocks fromthe extrusion device and delivering them in succession, each with awrapper, to a wrapping wheel, and operating gear for moving the liftingplunger in a triangular path, consisting of an upward lifting movement,then a substantially horizontal movement to slide said plunger clear ofthe block held in the wrapping wheel, and finally a diagonal returnmovement to thedown position.

2. In a machine for shaping and wrapping plastic materials, having anextrusion device for forming the plastic material into shaped blocks andan intermittently rotating wrapping wheel for wrapping the blocks soformed, said wrapping' wheel having a plurality of pairs of jaws, thecombination with the wrapping wheel of a reciprocating lifting plunger,means for delivering the shaped blocks from the extrusion device to saidlifting plunger when in the down position, and operating gear for thelifting plunger for imparting thereto:` at each machine cycle first anupward movement to lift a block and a wrapper into the jaws of thewrapping wheel, then a substantially horizontal sliding movement ctoclear the plunger from the undersurface of the block in said jaws andfinally a return movement to the down position, said return movementcommencing only after the plunger is clear of the block.

3. In a machine for shaping and'wrapping plastic materials, havinganextrusion device for forming the plastic material into shaped blocksand an intermittently rotating wrapping wheel for wrappingthe blocks soformed, said wrapping wheel having a plurality of pairs of jaws-thecombination with the wrapping wheel of a reciprocating lifting plunger,means for delivering the shaped blocks from the extrusion device to saidlifting plunger when in the down position, a horizontally reciprocatingcarriage, a parallel linkage carried thereon and supporting the liftingplunger, a lifting link connected to the parallel linkage and a pair ofcams, one for imparting reciprocating movement to the carriage and theother for imparting up and down movement to the parallel linkage,through the agency of the lifting link, said cams serving at each machine cycle first to move the plunger upwardsto deliver a block andwrapper to the wrapping -wheel, then to move the plunger substantiallyhorizontally to slide it clear of the undersurface of the block held inthe jaws,v and finally to return the plunger to its down position.

4.- In a machine forshaping and wrapping plastic materials, having anextrusion device for forming the plastic:A material into shaped blocksand an intermittently rotating wrapping wheel for wrapping the blocks soformed, said wrapping wheel having a plurality of pairs of jaws, thecombination with the wrapping wheel of a reciprocating lifting plunger,operating gear for the lifting plunger for imparting thereto at eachmachine cycle first an upward movement to lift a block and a wrapperinto the jaws of the wrapping wheel, then a substantially horizontalsliding movement to clear the plunger from the undersurface of the blockin said jaws and finally a return movement to the down" position, saidreturn movement commencing only after the plunger is clear of theIblock, a folder located at that side of the wrapping wheel to which theplunger moves in its horizontal sliding movement', said folder serving,on movement of the wrapping wheel, to fold the wrapper' against thebot.. tom of the block held in the lowermost pair of jaws, and means fordisplacing said folder out of the path of the plunger during saidhorizontal movement thereof. i

5. In a machine for conveying blocks of plastic material from anextrusion device to mechanism including a wrapping wheel for. wrappingthe blocks, means including a lifting plunger for successively`,receiving-the blocks from said extrusion device; and means for movingsaid lifting plunger cyclically in timed relation withthe operationofsaid extrusion device in a triangular path consisting of a rst pathover which the plunger has an upward lifting movement from a. positionclose tosaid extrusion device to a position wherein a block carried rIcythe plunger is delivered to said wrapping wheel. a secondpath whereinthe plunger is given a substantially horizontal movement to slide theplunger clear of a block held in said wrapping wheel, and a third pathwherein the plunger is given a diagonal return movement to the startingposition of said first path in time to receive the next successive blockfrom said extrusion device.

6. In a machine for' conveying blocks of plas-v tic material from anextrusion device to mechanism including a wrapping wheel for wrappingthe block's a. die chamber having a reciprocating die plunger 1providing 'the bottom `wall ci the' plastic material, the top of saidlifting plunger having a starting position level with the top of saiddie plunger inits upper position, said cover having a flange forsliding` from the top of said die plunger to the top of said liftingplunger the blocks successively ejected from the chamber by said dieplunger, means for cyclically raising said lifting plunger to a positionin which a block car- 1 ried thereby is delivered` to said wrappingwheel, and means for clearing said lifting plunger laterally away fromsaid wrapping wheel at the place where the block is delivered theretoand then returning said lifting plunger diagonally to said startingposition, said respective means operating cyclically intimed relationwith said die plunger and said coverl i f ALEXANDER RUSSELL.MATIHE'WPARKER. RICHARD NS'ON HARRIS.

